3/32x.775 Big Hub Wonder X-Hard. Big hubs have more bite and lower rolling resistance so important on modern high-speed tracks. Less sidewall deflection also makes them faster in the bankings. These tires feature the super tough, long, long wearing black rubber, which also has exceptional grip. In addition, it is unusually light in weight. This phenomenal compound has come to be called "Wonder Rubber" and it has taken wing car racing by storm. For years the performance of high powered slot cars have exceeded the capabilities of the tires making frequent tire changes necessary, but this remarkable compound is up to the test. It is particularly recommended for high speed racing in glue. This amazing rubber combined with Alpha's superior design, quality, and precision will give you the winning edge you are looking for. For any type wing car racing with glue, this is the tire of choice.